In order to reduce NO
x and the ignition loss generated by the pulverized coal combustion, the secondary gas fuel injection method is investigated at the pulveried coal combustion test facility (standard load: 6.54×10
5kcal/h). The secondary gas fuel injection method is to inject the gas fuel (H
2, CH
4, C
3H
8) in the flame for the NO
x reduction.
In the case of using CH
4 or C
3H
8 as a secondary fuel, the NO
x concentration is reduced for both combustion conditions of non-two stage combustion and stage combustion. But, H
2 doesn't have any effect for NO
x reduction.
For CH
4 or C
3H
8 injection, the NO
x reduction effect is different for the location of the injection point. At the case of non-two stage combustion condition, the better injection location for Nox reduction is distant from the burner and C
3H
8 is more effective at many points for injection than CH
4. On the contrary, at the case of two stage combustion the location near the burner is suitable for NO
x reduction in both CH
4 and C
3H
8 injection.
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